Service Valves
A service valve is utilized in air conditioning systems to regulate flow therein including full operational flow as well as cutting off the flow of refrigerant therein. Some modes of operation of a service valve have the option of utilizing a gauge to measure pressure at a point in the service valve and when configured appropriately to a loop in the overall system. A typical service valve is composed of four essential parts: 1. Line connection; 2. Compressor connection; 3. Valve stem; 4. Gauge port.
There are three positions in which the valve can be oriented that directly relate to the operational mode of the system: the valve stem out, the valve stem all the way in and finally the valve stem somewhere between the inwards and outwards position. A) If the valve stem is all the way out, the valve is considered to be in the back-seated position. The gauge port is closed and the valve is open, allowing refrigerant to flow through the system in a normal operating mode. B) If the valve stem is all the way in, the valve is considered to be in the front-seated position. The gauge port is open to the compressor connection and the refrigerant line (suction or discharge) connection is closed used for recovery and vacuuming; i.e., pumping system down.
Finally, C) if the valve stem is between the front-seated and back-seated position, it is considered to be in the mid-seated position. In this position all three connections the gauge port, line, and compressor are open. This allows the refrigerant to flow through the system and the system pressure to be read through the gauge port; it is also used for adding or removing refrigerant to the system as well as taking system readings. When placing the valve in its mid-seated position, it is best to have the valve in its back-seated position first and then turn the valve stem only one or two turns into the mid-seated position.
It should be appreciated that this type of service valve is useable with other devices connected thereto to its available ports. Additionally, the drawings are for purposes of exemplary illustration alone and that the corresponding threading of the valve stem for motion within the wall body of the valve is understood.
Gauge Port
A gauge port is a standardized device that typically has two access connections permitting the entry and exit of fluids therethrough. The port also has a point whereby a gauge measurement device can be connected thereto to enable the metering of pressure at the point of contact. There are various standardized gauge devices that are connectable to a gauge portion such as the Bourdon pressure gauge.
Manifold
A manifold is a pressure metering device having various valves and attachment points. A typical manifold comes with at least two valves and three attachment points to measure the high and low side pressure by attaching hoses to appropriate ports thereon and opening and close valves appropriately.
Prior Art Air Conditioning Educational Systems
Several demonstrator models exist in the air conditioning educational system prior art for effectively educating students as to several operational properties of air conditioning systems. Amongst these are the following US patents:
U.S. Pat. No. 1,547,091 to Baxter teaches a demonstrating device having a comparatively thin portable base having a representation of a refrigerator upon one of its sides, a fluid tight container detachably secured to one side edge of said base, said container having a duct communicating with its interior, a valve for controlling said duct, a conductor extending from said duct over the representation aforesaid, and means for said duct.
U.S. Pat. No. 2,329,453 to Brown teaches a refrigerator demonstrator comprising a replica of a household refrigerator cabinet having a door, an inner wall of said cabinet facing said door bearing a representation of a refrigerating system, and at least a portion of said wall being translucent so that light may pass therethrough from the rear to illuminate a corresponding portion of said representation.
U.S. Pat. No. 3,526,044 to Dwiggins teaches an automotive air conditioning system for simulating both normal and defective operation of a typical automobile air conditioning unit and various components thereof. The apparatus is scaled for portability and to be fully operated by commonly available electrical service through conventional outlets.
U.S. Pat. No. 3,694,934 to Barton teaches cooling system demonstrator means for demonstrating the action of a vehicle cooling system are disclosed comprising means for forcing liquid without heating the same under pressure into a vehicle radiator to simulate the heating and expansion of said cooling system from engine heat and means for withdrawing liquid without heating the same under suction from said radiator to simulate the cooling of said cooling system to ambient temperature.
U.S. Pat. No. 3,785,064 to Thomas teaches a method and apparatus for simulating the normal and abnormal operating conditions in an air-conditioning system comprising a plurality of mechanically and electrically operated working units functionally interconnected into a thermodynamic loop, including a plurality of simulating components responsive to control signals from a central control station for simulating desired conditions. The station includes a female receptacle for receiving a programmed plug-in board thereby automatically and simultaneously affecting the state of energization of certain of the simulating components and working units whereby certain of the working units will operate in an abnormal mode.
U.S. Pat. No. 3,934,356 to Bryant teaches a system of teaching a skill for service and repair of heating and air conditioning equipment, a teaching aid which incorporates a closed chamber, preferably insulated, which receives therein the air distribution portion of a heating and air conditioning system. The apparatus utilizes a complete miniaturized refrigerant system which has a sealed compressor unit, an evaporator, a condenser, and the appropriate lines connecting the various components. In the preferred embodiment, a removable skid mounted base supports the condenser and compressor.
U.S. Pat. No. 4,068,391 to Smith teaches a demonstration device for simulating the operation of a heat pump system comprising a schematic representation of a heat pump system, a plurality of lamps and associated electrical circuitry adapted to illuminate portions of the schematic representation to simulate the operation of the heat pump system in various modes of operation, and to simulate refrigerant flow and the phase state and temperature of the refrigerant at different places in the system, and associated explanatory panels for alternatively demonstrating the operation of the electrical circuitry of the heat pump system, or indicating the mode of operation of the system.
U.S. Pat. No. 4,623,312 to Crawford teaches a module for use in a training system assembly which includes a power base is multi-sided and includes mechanical-electrical feet on one side for jacking the module into the power base or into a second module. Detent spring latches are disposed on another side of the module for receiving the feet of a second module atop the first module. The module is hollow and an electrical component is mounted therein. The component is an electrical connection with the feet and the detent spring latches. A display is on a third side of the module and the rear of the module includes a fault selector switch which causes the component to be in either an operating configuration or a fault configuration.
U.S. Pat. No. 4,776,798 to Crawford teaches a changeable modular training system disclosed in U.S. Pat. No. 4,623,312 being extended to include an energy management microprocessing unit, i.e. CPU, a keyboard, a video screen, a remote sensor, and a microprocessing interface unit, to create an energy management microprocessing training system. These added components are formed in the same size modules and/or are interconnected, where needed, by the same electrical connectors and the same peg and slot supports as used in the changeable modular training system. This energy management microprocessing training system is used when students are taught how to program, operate, install, service, and troubleshoot mechanical and electronic control systems in a classroom, when using simulated control systems.
However, prior demonstrators such as U.S. Pat. No. 3,934,356 to Bryant typically have a refrigerant or other liquid therein that can harm students if a line is removed causing frostbite. Additionally, most do not have a complete picture of various operating points in the cycle. Thus, none of these provide for a simple way of demonstrating the air conditioning system in such as manner that the user does not have a high potential for being damage by frostbite.
Additionally, an effective air conditioning educational system would need to be able to teach Recovery, Recycling, Vacuuming, Standard Pressure Test and Charging of the system. None of the prior art devices and or systems provide these useful features and therefore do not completely educate a student as to the aforementioned.
Accordingly, there is a need to overcome the aforementioned problems.